This invention relates to a balloon catheter assembly comprising a detachable occluding balloon for occluding a path of a body fluid such as a blood vessel, and to a guide sheath for guiding the introduction of the catheter.
An occluding balloon is used for mainly occluding a blood vessel such as an artery when, for example, a percutaneous surgery of congenital cardiopathy due to patent duct arteriosus is carried out.
The PCT Patent Publication Sho 57-500720, for example, discloses a balloon catheter having an occluding balloon in which the balloon is separable at a required portion. However, this balloon catheter has the following problems:
Since the balloon has a complicated structure, it cannot be rendered small.
Further after the balloon has been expanded by accident, it cannot be contracted again.
Still further, it is feared that since the balloon is fitted only to the distal portion of the catheter, it may fall off by accident during its operation.
A similar balloon catheter is disclosed in the Japanese unexamined patent application publication Sho 59-34269. Since the balloon is also only fitted to a cannula, it may fall off by accident. If the connecting strength of the fitting portion is enhanced, the balloon can be prevented from falling off. However, it becomes difficult to separate the balloon from the catheter; the balloon gives an excess stress to the blood vessel to be occluded; and such a bulky structure of the balloon may cause the breakage thereof.
The balloon can be threadably connected to the catheter by means of screw. When the balloon is to be separated from the distal portion of the catheter assembly, however, the torque is not easily transmitted to the connecting portion of the balloon with the result that this may cause such trouble that the balloon would not be easily separated from the catheter, and the balloon would be twisted to be broken as well.
As a method of introducing an occluding balloon to a dwelling portion of blood vessel, such as a peripheral blood vessel e.g. a cerebral blood vessel, the balloon is slightly expanded in advance to be carried by a blood stream. However, this method is not suitable for sending an occluding balloon to a vascular portion where a blood flow is rather weak. This method is not applicable to the transmission of the balloon to the vicinity of a heart.
The method of transmitting an occluding balloon in a blood vessel while exposing the balloon as disclosed in the PCT Patent Publication Sho 57-500720, will not only lead to the breakage of the balloon but makes it difficult to easily and accurately transmit the balloon to the required dwelling portion.
This invention provides a balloon catheter assembly in which a balloon does not easily fall off during the transmitting operation thereby ensuring the introduction of the balloon to the required portion to be occluded, and, even if the balloon is expanded by accident, it can be contracted to the original size if a filler has not yet been gelled.
This invention further provides a balloon catheter assembly in which an operator can easily observe how a balloon occludes the required portion.
The invention still further provides a balloon catheter which is simple in structure and in which a balloon can be rendered small and can not be easily broken.